The invention is particularly appropriate for mirrors having large dimensions; typically the largest dimension being greater than 1.5 m.
At present, mirrors having large dimensions are produced either by assembling a plurality of optical surfaces having small dimensions, or by the overall production of a large monolithic mirror.
Mirrors produced by assembling a plurality of optical surfaces having small dimensions have to be associated with an active system making it possible to move the optical surfaces with respect to each other in order to optimize the alignment of the optical surfaces.
A second solution consists of manufacturing a mirror by assembling optical surfaces having smaller dimensions which are then polished. In this case, the areas of assembly of the optical surfaces (assembly by bonding, brazing welding, etc.) form part of the mirror and must therefore be as stable as the optical surfaces of the mirror.
A third solution consists of producing a monolithic mirror. This type of method necessitates production means of sufficient size for producing the structure of the mirror. The production of mirrors using this method is costly or even impossible for mirrors having very large dimensions.